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901.
902.
东海沿海季节性海平面异常成因 总被引:1,自引:0,他引:1
Based on the analysis of sea level, air temperature, sea surface temperature(SST), air pressure and wind data during 1980–2013, the causes of seasonal sea level anomalies in the coastal region of the East China Sea(ECS) are investigated. The research results show:(1) sea level along the coastal region of the ECS takes on strong seasonal variation. The annual range is 30–45 cm, larger in the north than in the south. From north to south, the phase of sea level changes from 140° to 231°, with a difference of nearly 3 months.(2) Monthly mean sea level(MSL)anomalies often occur from August to next February along the coast region of the ECS. The number of sea level anomalies is at most from January to February and from August to October, showing a growing trend in recent years.(3) Anomalous wind field is an important factor to affect the sea level variation in the coastal region of the ECS. Monthly MSL anomaly is closely related to wind field anomaly and air pressure field anomaly. Wind-driven current is essentially consistent with sea surface height. In August 2012, the sea surface heights at the coastal stations driven by wind field have contributed 50%–80% of MSL anomalies.(4) The annual variations for sea level,SST and air temperature along the coastal region of the ECS are mainly caused by solar radiation with a period of12 months. But the correlation coefficients of sea level anomalies with SST anomalies and air temperature anomalies are all less than 0.1.(5) Seasonal sea level variations contain the long-term trends and all kinds of periodic changes. Sea level oscillations vary in different seasons in the coastal region of the ECS. In winter and spring, the oscillation of 4–7 a related to El Ni?o is stronger and its amplitude exceeds 2 cm. In summer and autumn, the oscillations of 2–3 a and quasi 9 a are most significant, and their amplitudes also exceed 2 cm. The height of sea level is lifted up when the different oscillations superposed. On the other hand, the height of sea level is fallen down. 相似文献
903.
904.
基于证据加权模型的青海拉陵灶火地区矿产靶区预测及效果评价研究 总被引:1,自引:0,他引:1
当代矿产资源评价是复杂高维非线性系统的建模与评价过程,建立能够描述综合信息间复杂关系的多元非线性统计模型并预测矿产靶区,对矿产勘查具有重要指导意义。本文基于GIS软件平台,将证据加权模型应用于青海拉陵灶火地区矿产靶区预测,提取研究区成矿地质背景信息,遥感地质信息,地球化学异常信息等17种致矿综合信息,建立研究区矿产靶区预测模型,绘制成矿后验概率分布图,并利用ROC曲线分析方法对预测结果进行效果评价,根据ROC曲线的TP率和FP率计算圈定矿产靶区概率阈值,对研究区矿产靶区进行了圈定,结果表明证据加权和ROC曲线分析相结合圈定的成矿靶区与已知矿点分布较为吻合,该方法用于矿产靶区预测具有一定的可行性。 相似文献
905.
Tidal current energy is prominent and renewable. Great progress has been made in the exploitation technology of tidal current energy all over the world in recent years, and the large scale device has become the trend of tidal current turbine (TCT) for its economies. Instead of the similarity to the wind turbine, the tidal turbine has the characteristics of high hydrodynamic efficiency, big thrust, reliable sealing system, tight power transmission structure, etc. In this paper, a 1/5th scale horizontal axis tidal current turbine has been designed, manufactured and tested before the full scale device design. Firstly, the three-blade horizontal axis rotor was designed based on traditional blade element momentum theory and its hydrodynamic performance was predicted in numerical model. Then the power train system and stand-alone electrical control unit of tidal current turbine, whose performances were accessed through the bench test carried out in workshop, were designed and presented. Finally, offshore tests were carried out and the power performance of the rotor was obtained and compared with the published literatures, and the results showed that the power coefficient was satisfactory, which agrees with the theoretical predictions. 相似文献
906.
907.
基于孢粉数据的珠江三角洲QZK6孔全新世气候定量重建 总被引:1,自引:1,他引:0
依据珠江三角洲QZK6钻孔孢粉组合特征及AMS14C测年结果,基于CONISS软件对剖面孢粉组合进行分带分析,其结果分为A、B、C和D四个孢粉带。根据10981a cal BP以来的孢粉组合特点,结合东亚孢粉数据库中位于广东的122个天然植被下的表层土壤样点的孢粉组成特征,利用软件Polygon 1.5定量重建了QZK6孔的全新世古气候参数。结果显示,全新世气候基本以暖湿为主,总体趋势为凉干—热湿—温凉;D带(10981~8500a cal BP)年均温度为21.7~22.1°C,年降水量1778~1888mm,年均温度和年降水量均比较高;C带(8500~8105a cal BP)年均温度为21.9~22.3°C,年降水量为1845~1929mm,达到各带中最高值;B带(8105~4343a cal BP)年均温度和年降水量开始降低,年均温度为20.8~21.7°C,年降水量为1595~1806mm。人类活动从B带开始增强(在A带达到最强);A带(4343a cal BP至今)年均温度为20.3~21.5°C,年降水量为1587~1765 mm,为各带中年均温度最低、年降水量最少的阶段。 相似文献
908.
909.
陆态网络连续运行基准站(简称CORS站)是中国2000国家大地坐标框架的重要骨架支撑。以陆态网络CORS站观测时间序列为研究对象,采用经典差分自回归移动平均模型对253个CORS站进行时间序列拟合分析。实验结果表明该模型能够较好的拟合绝大部分测站的时间序列,拟合后剩余残差序列明显减小且更加收敛。 相似文献
910.
Transportation of floating structures for long distance has always been associated with the use of heavy semi transport vessel. The requirements of this type of vessel are always special, and its availability is limited. To prepare for the future development of the South China Sea deepwater projects, COOEC has recently built a heavy lift transport vessel — Hai Yang Shi You 278 (HYSY278). This semi-submersible vessel has displacement capacity of 50k DWT, and a breath of 42 m. Understanding the vessel’s applicability and preparing its use for future deepwater projects are becoming imminent need. This paper reviews the critical issues associated with the floating structure transportation and performs detailed analysis of two designed floating structures during transportation. The newly built COOEC transportation vessel HYSY278 will be used to dry transport the floating structures from COOEC fabrication yard in Qingdao to the oil field in the South China Sea. The entire process will start with load-out/float-off the floating structures from the construction sites, offload the platform from the vessel if needed, dry transport floating structures through a long distance, and finally offload the platform. Both hydrodynamic and structural analyses are performed to evaluate transport vessel and floating structures. Critical issues associated with the transportation and offloading of platform from the vessel will be studied in detail. Detailed study is performed to evaluate the response of the system during this phase and additional work needed to make the vessel feasible for use of this purpose. The results demonstrate that with proper modifications, HYSY278 can effectively be used for transporting structures with proper arrangement and well-prepared operation. The procedure and details are presented on the basis of study results. Special attentions associated with future use will also be discussed based on the results from analysis. 相似文献